Influence of Thermal Contact Resistance of Aluminum Foams in Forced Convection: Experimental Analysis

Abstract

In this paper, the heat transfer performances of aluminum metal foams, placed on horizontal plane surface, was evaluated in forced convection conditions. Three different types of contacts between the sample and the heated base plate have been investigated: simple contact, brazed contact and grease paste contact. First, in order to perform the study, an ad hoc experimental set-up was built. Second, the value of thermal contact resistance was estimated. The results show that both the use of a conductive paste and the brazing contact, realized by means of a copper electro-deposition, allows a great reduction of the global thermal resistance, increasing de facto the global heat transfer coefficient of almost 80%, compared to the simple contact case. Finally, it was shown that, while the contribution of thermal resistance is negligible for the cases of brazed and grease paste contact, it is significantly high for the case of simple contact.

Design and Thermal Comparison of Random Structures Realized by Indirect Additive Manufacturing

“…The global HTC* of the different aluminum foams shows the same evolvement for the various imposed air speeds. The value of HTC* obtained for the commercial foam with an air speed pair to 5 m/s is in accordance with literature [21]. The results demonstrate that the HTC* rises with increasing air flow rate and it varies in a range between 256 and 870 W/m 2 ·K depending on the PPI value.…”

“…Metal foams are receiving attention due to their combinations of various thermal, mechanical, and acoustic properties that provide potential opportunities for diverse multifunctional structural applications [8,9]. In particular, they have high specific strength [10,11,12,13,14], high specific strain [15,16,17], excellent impact absorption [18,19], acoustic insulation [20], and compact heat exchangers [21,22,23,24,25,26]. The main problems related to their production are the control of porosity distribution [27,28] and the assembly of foams with other components.…”

Design and Mechanical Characterization of Voronoi Structures Manufactured by Indirect Additive Manufacturing

“…However, expensive machineries, as well as low surface finishing and demanding process settings, limit the application of these methodologies in industrial environments [7]. Metal foams are composed of biphasic and cellular materials, which combine good mechanical resistance with excellent thermal and acoustic properties [8].In particular, high specific strength [9][10][11][12][13] and strain [14][15][16], excellent energy absorption [17,18], acoustic insulation [19], and heat dissipation media [20][21][22][23][24] make this class of materials increasingly useful for several multifunctional applications. The main problem afflicting metal foams regards the manufacturing process, and specifically the porosity distribution [25,26], as well as the connection with other components.…”

FEM Simulations for the Optimization of the Inlet Gate System in Rapid Investment Casting Process for the Realization of Heat Exchangers

“…7 Indeed, metal foams have already been applied in heat exchange prototypal devices. 3,22,32,38 In heat exchange devices, this is important as such the contact between these surfaces and flat heat pipes. Through RIC, it is possible to integrate metallic reticular structure branches within the tube wall bulk in the fundable model.…”